It is not clear how to set different timezones for meetings on the phone app version of outlook. I have figured out how to do this on the cloud based version.
I've added Outlook via it's PWA ability into the dock of my Mac and everytime I start it, it asks for my language preferences and timezone. It looks like, it doesn't save/remember what I've set earlier. Would be really good that Outlook remembers this (via LocalStorage for example or Cookie) setting.